Does the action using the expression builder to expand it and getting values from the passed feature attribute map. substitutionMap is used to pass custom substitutions, to replace each key in the map with the associated value

Expands the given action using the expression builder This function currently replaces each expression between [% and %] placeholders in the action with the result of its evaluation on the feature passed as argument.

Additional substitutions can be passed through the substitutionMap parameter